Nice piece of software.
Why do you state: "consider your hardware wallet as compromised..."
Greetz
Roland
Well, once you export even a single private key and store it unencrypted on a device that's online, there is a very remote possibility it was/is compromised.
An attacker that steals this private key, and gets his hands on your xpub, can (theoretically, so i'm told) work back to calculate your xprv...
It's basically just being paranoid, but i wouldn't want a single private key derived from my xprv from my hardware wallet ever to touch an online device... Odds are extremely small something bad will happen, but still, there is a very remote possibility.